Typically, a flat, sheet-like workpiece, for example, a sheet of glass, a small iron sheet which is to undergo galvanizing, a ceramic board, etc., are removed separately from a heaped pile of a plurality of such workpieces prior to processing and thereafter, are transferred to a carrying apparatus. Once transferred to the carrying apparatus the workpiece is automatically transferred thereby to a processing installation, for example, a plating bath or a washing bath, and is immersed therein. After the passage of a predetermined time period, the workpieces are picked up, transferred from the processing installation and released from the carrier so as to be put into a receiver, piece by piece. Many kinds of such carrying systems are well known.
For example, Japanese patent, Hei 1 (1989)-42632, discloses a metal plating method in which, after an electronic device is attached on a lead frame and packaged within synthetic resin, said lead frame is taken out individually from a stocking container or cassette and is clamped by a clamping finger on a continuously moving conveyor. Thereafter, said lead frame is dipped into a plating bath. After the plating has been completed, said lead frame is placed into a container.
In another Japanese Laid-Down patent, Hei 2 (1990)-277800 and in U.S. Pat. No. 4,775,046, other sheet processing apparatuses are publicly disclosed in which resilient means for clamping the sheet-like piece are attached on an endless flat belt such that one end of the resilient clamping means is attached on the belt and a free clamp section, which is on the other free end of said clamping means, serves to clamp the sheet-like piece between the free clamp section and the belt itself.
In the above-described carrying apparatus, however, no description is provided with respect to means which transfers the workpiece without error from a standstill to the clamping device which clamping device is moving together with the movement of the endless belt or conveyor.
Also, in the above-described examples, a chemical solution being used in the processing of the workpiece remains on the clamping section of the fixing or clamping means. Such chemical solution which remains on the clamping section may cause shading or erosion of the workpiece surface after processing.
Still further, the carrying device which incorporates an endless belt or sheet as a main component thereof has the resulting defects wherein the life span of said carrying belt is relatively short and the cost of maintaining or exchanging the old belt with a new one requires considerable expenditure.
An object of the present invention is to provide an inexpensive carrying apparatus, the efficient performance of which is assured by the use of a roller chain.
To solve the aforementioned problems, the carrying apparatus of the invention which is provided for the transport of the thin, sheet-like workpieces comprises an endless roller chain belt that circulates continuously and moves on a circular track. The roller chain belt includes a plurality of mutually adjacent link plates which each include an outer link plate. The roller chain belt further includes a fixing attachment having an L-shaped cross section which fixing attachment is disposed on One side of each outer link plate of the roller chain belt.
A plurality of fixture plates also are secured to the roller chain wherein each fixture plate is fixed on and supported by two mutually adjacent fixing attachments located respectively on each pair of adjacent link plates. Each fixture plate is formed with a plurality of vertical, interrupted slot lines which each preferably comprise three slot sections. The three slot sections are aligned end to end in a spaced apart relation. The fixing plates further include a work holding device or fixture which is formed of a spring wire and includes a single-turn coil section formed intermediate the opposite ends of the work holding device.
The work holding device is oriented along said slot line so that the coil section of the spring wire extends through the middle slot of the three slots described herein and remains on one side of the fixture plate. The opposite ends of the work holding device that are disposed on opposite sides of the coil section respectively define a fixing section and a work holding section which respectively extend through the upper slot section and lower slot section of the three slot sections to the opposite side of the fixture plate. The fixing section is secured to the fixture plate and the work holding section is freely movable toward the fixture plate by the resiliency of the spring wire and away from the fixture plate by a manipulation of the work holding device. Thus, the sheet-like thin workpiece can be held between said work holding section at the end of the coiled-wire work holding device and an end section of the fixture plate.
More particularly, the middle slot of the three slot sections of the vertical slot line is cut with an inclined angle or in other words is skewed relative to the upper and lower slot sections and acts as a seat for supporting the coil section. The inclined angle of the middle slot matches the winding angle of the coil section of the work holding device while the other two slots, i.e. the upper slot and the lower slot, are oriented parallel to a vertical line which defines a main longitudinal axis of the vertical slot line. The vertical axes of the upper and lower slots, however, are disposed so as to be slightly offset on opposite sides of the longitudinal axis with a detached space between the two vertical axes of the upper and lower slots and the main longitudinal axis of the slot line. Thus, the two opposite ends of the coil section, in other words the fixing section and the holding section, are oriented so as to be located on a common vertical line.
The carrying apparatus of the thin sheet-like workpiece also has a square notch which is cut at the lower end of the fixture plate and in which fits the holding section of the holding device which is adjacent the coil section. The square notch opens downwardly from the lower edge of the fixture plate at the lower end thereof. The section of the fixture plate which is disposed between an adjacent pair of said square notches is defected such that the end of the defected section will be disposed or located at a location vertically higher than the liquid level of the chemical liquid in which the workpiece is being immersed, thus preventing the immersing liquid from remaining on the end of the fixture plate after processing.
The carrying apparatus of the thin, sheet-like workpiece also has an insulating ring or mantle made of insulating material which ring is located at a fixing section of a bolt which bolt fixes the fixture plate to the fixing attachment. The bolt also includes an insulation sleeve through which the connecting bolt is inserted and which serves to connect the fixture attachment and the fixture plate to maintain insulation of the connecting bolt from the fixing attachment.
In operation, the workpiece to be processed is held resiliently between the fixture plate and a lower end of the holding section which holding section is the end section of each of the plurality of coil springs extending through the fixture plate.
The defected, square notch of the fixture plate serves to prevent the chemical liquid from remaining at the end of the fixture plate and instead to flow downwardly therefrom. By adjusting the location and shape of the slots, the holding device of the spring coil is firmly fixed.
In addition, the connecting bolt is insulated from the fixing attachment of the chain links and consequently, the fixture plate is also insulated from the fixing attachment. Thus, at a time when an electric current flows through the fixing bolt, the electric current does not leak to other structures of the carrying apparatus other than the fixture plate itself.
Other objects and purposes of the invention, and variations thereof, will be apparent upon reading the following specification and inspecting the accompanying drawings.